Allantoin is known to possess soothing, keratolytic moisturizing and anti-irritant properties. Various aluminum salts of allantoin are described in U.S. Pat. No. 2,761,867. These compounds combine the soothing and healing properties of allantoin with the astringent properties of aluminum and have found use in a variety of external cosmetic compositions and internal medicaments. For example, cosmetic chemists have utilized allantoin and allantoin salts in formulating a variety of products such as deodorants, antiperspirants, astringent lotions, after-shave lotions, diaper creams and the like. An alcohol-soluble aluminum chlorhydroxy allantoin propylene glycol complex useful in the formulation of various cosmetic compositions is described in U.S. Pat. No. 3,632,596.
Ascorbic acid (Vitamin C) has found use primarily in the prevention and treatment of scurvy. It has also found use as an antioxidant for fats, oils, aqueous oil emulsions, soft drinks and for the prevention of browning and off-flavors in frozen foods (See Kirk-Othmer, Encyclopedia of Chemical Technology, 2nd Edition, Vol. 2, p. 747 et seq. Interscience, 1963). It has also been reported that a one percent solution of ascorbic acid is an effective palliative for pain when applied topically to patients suffering from severe and extensive burns.
Ascorbic acid is quite stable in dry form although it gradually darkens on exposure to light. Solutions of ascorbic acid are sensitive to alkalis and acids. Ascorbic acid is also sensitive to heat; in fact, the viamin is readily oxidized if heated in air. The vitamin is known to deteriorate rapidly in the presence of even traces of metals such as copper and silver and is sensitive to iron and manganese. Despite its widespread use when taken internally for the prevention and treatment of a wide variety of maladies, ascorbic acid has not been utilized in the formulation of cosmetic compositions and topical medicaments because of its sensitivity to light, alkalis, acids, heat and metals and the like.
It is an object of this invention to provide novel compounds containing allantoin or aluminum salts of allantoin and ascorbic acid which are stable both in dry form and solutions and are not sensitive to heat.
It is another object of this invention to provide novel compounds possessing the soothing and healing action of allantoin, the astringent and deodorizing actions of aluminum salts of allantoin and the pain relieving and antioxidant properties of ascorbic acid.
Other objects will become apparent from a consideration of the following specification and claims.